Super-stretchy, Self-healing, Tunable Polymers

June 19, 2019

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Scientists demonstrate the polymer healing process and recovery of extreme stretchability.
Scientists demonstrate the polymer healing process and recovery of extreme stretchability.
Image courtesy of Oak Ridge National Laboratory

The Science

A novel self-healing material stretches up to 5,600%. The team controlled the polymer’s super-elastic and self-healing properties by tuning its rubbery segments and the connectors between each segment. When damaged, the rubbery polymers (called elastomers) completely heal in 120 minutes at room temperature. They heal in 20 minutes at slightly higher temperatures. Healing fully restores the material and lets it go back to work.

The Impact

After a cut, the super-stretchy material heals itself and resumes working (for example, separating gases). This self-healing feature could lead to longer lasting, better performing films and other products. The novel elastomers illustrate a synthetic approach to promising materials for use as films, membranes, coatings, and other devices.

Summary

Novel polymeric elastomers are an attractive platform for creating materials capable of extreme stretching, absorbing energy during vibration, and repairing damage from cuts and tears. In this study, scientists controlled the elastic segments by using rubbery polymer spacers between hydrogen-bonding connectors and varying the number of hydrogen-bonded connections between the segments. This resulted in ultimate elastomer elongation of 984% to 5,600% with tunable resilience and toughness. The elastomers also exhibited excellent acoustic and vibration damping properties and quickly recovered from being stretched. After mechanical damage, elastomers could be healed—with complete restoration of mechanical performance—in 120 minutes at room temperature. Healing took less time at increased temperature. Healed elastomers recovered their permeability and selectivity in separation of gases. The super-stretchy materials could be useful, for example, in self-healable functional surfaces, membranes, and mechanical energy absorbers (such as vibration dampers).

Contact

Tomonori Saito
Oak Ridge National Laboratory
saitot@ornl.gov  

Funding

The Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division and the Office of Fossil Energy, Carbon Capture Program (gas separation measurements); Oak Ridge National Laboratory Technology Innovation Program (gas separation measurements); National Science Foundation Polymer program (rheological measurements); and University of Tennessee (start-up grant, density functional theory calculations) funded this work. The team used resources at the Center for Nanophase Materials, a DOE Office of Science user facility.

Publications

P.F. Cao, B. Li, T. Hong, et al., “Superstretchable, self-healing polymeric elastomers with tunable properties.” Advanced Functional Materials 28, 1800741 (2018). [DOI: 10.1002/adfm.201800741]

Related Links

Oak Ridge National Laboratory story tip: Chemistry—Polymer, heal thyself

Alliance for Manufacturing Foresight article: Self-healing polymers moving forward